Impact-resistant and rigid polyamide compositions

ABSTRACT

A molding composition including a thermoplastic processable polyamide, an elastomer, and an epoxy having a plurality of epoxide groups.

This application is a continuation of application Ser. No. 07/463,779, filed Jan. 8, 1990, now abandoned, which is a continuation of application Ser. No. 219,996, filed Jul. 15, 1988, now abandoned.

The present invention is directed to impact-resistant and rigid polyamide compositions, more specifically such compositions which provide a high measure of rigidity and dimensional stability.

BACKGROUND OF THE INVENTION

Polyolefins have poor compatibility with a polyamide matrix. As a result, it is difficult to obtain blends which are both processable and practical and various expedients have been adopted in an attempt to solve this problem.

British Patent 998439 (German 1,241,606) teaches achieving high impact resistance by mixing two polyolefins into the rigid polyamides. In order to overcome the incompatibility problem, the olefins have unsaturated carboxylic acids grafted thereon.

Swiss Patent 649566 seeks to solve the same problem by introducing polyolefins based upon ethylene, propylene, and 1,4-hexadiene or 2,5-norbornadiene. These materials are activated by the introduction of α, β unsaturated dicarboxylic acids, anhydrides, or esters. Thus, the high bending E-modulus of the polyamide is modified by the unsaturated additives. Molded shapes prepared from such compositions have good impact and notched bar impact properties and high ductility. However, they are not sufficiently rigid, nor are they dimensionally stable. In other words, they have a great tendency to creep, which makes them unsuitable for many uses.

Another approach to the same problem is the introduction of core/shell polymers or grafted copolyolefins into rigid amorphous copolyamides. Such compositions are disclosed in U.S. Pat. Nos. 4,410,661 and 4,536,541. However, mixtures of the foregoing type exhibit substantial and undesirable shrinkage at elevated temperatures, even after only a short period of time. Therefore, shapes produced from such compositions are unsuitable for any use wherein exposure to elevated temperatures is involved.

A narrower improvement is shown in German 3,436,362, wherein rigid polyamides derived from terephthalic acid, isophthalic acid and alkanediamines form the basic material. To this is added copolymers of ethylene and/or acrylates to which carboxyl groups are grafted.

European Patent 27,198 teaches the addition of a core/shell polymer as a modifier of impact resistance. Acrylic acid derivatives are grafted onto a polybutadiene or butadiene/styrene core. This improves the impact resistance, but results in a substantial loss in stiffness. The patent teaches compensating for this loss by the addition of glass fibers.

U.S. Pat. No. 4,180,494 teaches the impact-resistance modifiers of the present invention, and German 3,339,000 teaches the use of similar core/shell polymers in conjunction with polyamides. However, molded shapes of this character are usually unsatisfactory, as they are not dimensionally stable. In particular, they tend to creep and to be highly susceptible to shrinkage under heat.

British Patent 1,069,176 seeks high thermal and dimensional stability for molded shapes by the addition of cross-linking diepoxides.

British 1,376,537 and German 2,144,687 introduce epoxide resins into plastomeric materials. These are substantially dimensionally stable and rigid; however, their impact-resistance is insufficient. Moreover, the presence of a high concentration of fillers and reinforcing agents produces a high density which, in many cases, is to be avoided.

Thus, there is a substantial need for polymeric materials which are impact-resistant, rigid, and dimensionally stable. In addition, such materials should be capable of simple injection molding. Such materials are used as casings and other protective parts in machines, vehicle bodies, etc.

BRIEF DESCRIPTION OF THE INVENTION

It is, therefore, desirable to provide molding compositions which are impact-resistant, rigid, dimensionally stable, without an excessive increase in density. Such products should have minimal creepage and shrinkage.

In accordance with the present invention, the foregoing requirements are met by the use of thermoplastic, processable polyamide compositions which contain an elastomer impact resistance modifier and an epoxide having more than one epoxide group.

In particular, it has been found that the combination of the epoxy compound and the impact resistance modifier in the polyamide produces a synergistic effect. The amount of modifier can be substantially reduced without impairing the desired impact properties. As a result, an improved relationship between resistance and rigidity can be obtained. Moreover, cost savings can also be realized. The shapes made from the foregoing materials are particularly stable and have minimal shrinkage when subjected to elevated temperatures.

DETAILED DESCRIPTION OF THE INVENTION

Polyamides which have been used as molding materials are generally useful in the present invention.

For example, specific mention is made of semicrystalline and amorphous copolyamides, e.g. those made from diamines and acidic monomers. Suitable diamines include hexamethylene diamine and its derivatives, mono and dicycloaliphatic diamines and derivatives thereof (especially of the alkylated bis(4-aminocyclohexyl)methane type) etc. The acids comprise isophthalic acid and terephthalic acid which may be substituted by other aromatic or aliphatic dicarboxylic acids.

Polyamide 6; polyamide 6,6; polyamide 6,10; polyamide 11; polyamide 12; and polyamide 6,12 have all been found to be suitable. Typical ether amides are reaction products of H₂ N--(R--O)_(n) R--NH₂ with dicarboxylic acids. The ether ester amides have ester linkages in addition to the --NH--CO-- linkages. The foregoing materials are preferably used in amounts of at least 40% by weight of the total molding composition.

The molding compositions preferably contain at least 3% by weight of the impact resistance modifying material, based upon the total molding composition. More preferably, 5 to 30% by weight is used and 10 to 20% by weight is most desirable.

Such modifiers include copolymers of α olefins which are activated by subsequent grafting with an unsaturated copolyolefin, preferably an α-unsaturated acid, and most preferably 1.0 mol % of an unsaturated dicarboxylic acid. This results in a maximum of 2.0 mol % carboxylic groups; ethylene is not more than 90 mol %, the rest preferably comprising propylene and/or 1-butene. Also, core/shell polymers are suitable. Preferably, these comprise a copolyolefin core which contains a butadiene or acrylate, and a shell of grafted vinyl compounds, e.g. acrylates. The metallic salts of the grafted copolymers (Ionomers) are not recommended because of the decrease in the number of adhesion sites.

Epoxy compounds suitable for use in the present invention are those which have at least two epoxy groups. Preferably, these are terminal, i.e. located at the ends of the molecule. Of special desirability are those epoxies having more than one glycidyl ether group in the molecule. They increase the molecular weight by linking the polyamide molecules. Very small amounts are sufficient; often an optimum can be found at less than 1% by weight, based on the total molding composition. It is preferred to use 0.05 to 5% and most preferred to use 0.1 to 1.0%, based on the molding composition. Polymeric epoxy compounds containing at least two epoxy groups or glycidyl groups in each molecule are also useful in the present invention.

Diglycidyl ethers having the formula Y--O--X--O--Y have been found especially advantageous. Y is an epoxide carrying radical and X is a divalent radical taken from the class consisting of alkyl having 2 to 10 carbons and aralkyl having 7 to 20 carbons. Those which are derivatives of neopentyl glycol and/or bisphenol A are deserving of particular mention.

Preparation of the compositions of the present invention is substantially conventional. The ingredients are premixed in the usual types of apparatus; such as, vibrating mixers, stirring mixers, mills, or phase mixers. Processing takes place in the melted form using screw machines such as extruders or plasticorders. These devices produce the compositions as granulates, strands, etc. which are then formed in injection molding machines or extruders in the usual manner.

Of course, normal additives, such as stabilizers, pigments, lubricants, emulsifiers, release agents, colorants, flame retardants, mineral or metallic fillers, reinforcing agents, etc. can all be included as needed.

EXAMPLES

The polyamide starting material was mixed sequentially with the impact resistance modifier and the epoxy compound. The combination was homogenized on a Werner Pfleiderer ZSK 30 two-phase extruder at 220° to 290° C. Thereupon, extrusion took place to yield a strand which was comminuted to form a uniform granulate. The granulate was dried under nitrogen at 80° to 90° C. and a vacuum of 30 to 50 mbar. Test bodies were then prepared using an Arburg extruder (type 320-210-250) and the various properties of the test bodies were measured.

The results are shown in Tables I to V herein. Some of the samples contain no epoxy and constitute comparisons with the prior art. The compositions set forth in Tables I to IV contain copolyolefin modifiers derived from ethylene, propylene, 1-butene modified with maleic acid anhydride. Table V displays the results of tests using the core/shell polymer. The melt viscosities are in Pas at 270° C. and 122.6N.

The impact and notch resistances were measured according to DIN 53453 dry at 23° C. No break is indicated by nb. The bending E modulus and the limit bending stress were determined in accordance with DIN Norm 53452 and the shrinkage values in the longitudinal direction are in accordance with DIN tension bars 53445/3. They were measured after storage for 24 hours in a circulating air oven at 100° C. and, in another test, for 1 hour at 140° C. The shrinkage values were determined for DIN tension bars 53445/3 after dry storage for 24 hours after injection molding. The values are given in percentages.

In Tables I, V and VI, polyamide 6 (melting point 221° C.) was used. In Table II, an amorphous polyamide which is the reaction product of hexamethylenediamine and isophthalic acid was the starting material. It had a glass transition temperature of 140° C.

Table III shows the results of the use of Grilamid TR 55 (T_(g) 155° C.) which is also described in U.S. Pat. No. 4,356,300. Table IV describes the use of polyamide 12 having a melting point of 178° C. All the foregoing polyamides are commercial products of EMS-Chemie AG of Domat/Ems, Switzerland.

The preferred epoxy compound of Tables I to V is neopentyl diglycidyl ether, also known as 2,2'-(2,2-dimethyl-1,3-propanediyl)-bis(oxymethylene)bisoxirane. In Table II, test (1), 1,4-butanediglycidyl ether was used. Table VI shows the use of the diglycidyl ether derived from bisphenol A. G1302, a product of EMS-Chemie AG, has a molecular weight of 385.

                                      TABLE I                                      __________________________________________________________________________     Polyamide 6 - moulding materials with impact-resistance-modifier derived       from dicarboxylic acids-grafted copolyolefines                                 __________________________________________________________________________                               5    6    7                                                    2         4     Impact                                                                              Notch                                                                               Bending                                              Impact-                                                                             3    Melt  Resis-                                                                              Impact                                                                              E Modu-                                         1    Resis-                                                                              Digly-                                                                              Viscos-                                                                              tance                                                                               Resist                                                                              lus                                        0    Poly-                                                                               tance                                                                               cidyl                                                                               ity   23° C./                                                                      23° C./                                                                      23° C./                             Test amid-                                                                               modifier                                                                            ether                                                                               (270°/                                                                        dry  dry  dry                                        No.  wt. %                                                                               wt. %                                                                               wt. %                                                                               122.6N)                                                                              kJ/m2                                                                               kJ/m2                                                                               N/mm2                                      __________________________________________________________________________     (a)  PA 6  0   0     350  nb    6.0 2000                                       A28  100                                                                       pure                                                                           (b)  PA 6  0   0.4  `403  nb    4.1 2645                                       E 5006                                                                              99.6                                                                      (c)  PA 6 15   --    578  nb   35.4 1203                                       E 5179                                                                              85                                                                        (d)  PA 6 15   0.2  1363  nb   38.1 1950                                       E 5178                                                                              84.8                                                                      (e)  PA 6 15   0.4  1342  nb   44.7 1940                                       E 5005                                                                              84.6                                                                      (f)  PA 6 15   0.5  1032  nb   53.3 1870                                       E 5487                                                                              84.5                                                                      (g)  PA 6 12   0.5  1177  nb   32   2160                                       E 5180                                                                              87.5                                                                      (h)  PA 6 10   1.0  6071  nb   39   1243                                       E 4913                                                                              89.0                                                                      (i)  PA 6 10   3.0  >10000                                                                               nb   69.5 2625                                       E 4796                                                                              87.0                                                                      (k)  PA 6 20   0.4   681  nb   14.3 1667                                       E 5007                                                                              73.6                      (-40°)                                                                  50.4                                            (e)  75   20   5.0  >10000                                                                               nb   nb   2045                                       E 4575                                                                         (l)  77.7   19.4                                                                              2.9  2065  nb   66.6 2039                                       E 4574                    nb   30.6                                            (E 3752)                  (-20°)                                                                       (-20°)                                   (m)  80   20   --    136  nb   42   1517                                       A 28NZ                                                                         __________________________________________________________________________                   10        12                                                          8    9   Elon-                                                                              11    Exten-                                                      Limit                                                                               Yield                                                                              gation                                                                             Tensile                                                                              sion                                                                               13     14                                          0    Bending                                                                             Stress                                                                             at  Strength                                                                             at  Shrinkage                                                                             Shrinkage                                   Test Stress                                                                              23° C./                                                                     Yield                                                                              23° C./dry                                                                    Break                                                                              after  after                                       No.  N/mm2                                                                               dry %   N/mm2 %   24 h/100° C.                                                                   1 h/140° C.                          __________________________________________________________________________     (a)  100  85  10  55     10 -0.36  -0.75                                       A28                                                                            pure                                                                           (b)  109  --  --  --    --  -0.22  -0.32                                       E 5006                                                                         (c)  84     57.3                                                                             7.0 42      17.2                                                                             -0.38  -0.47                                       E 5179                                                                         (d)  83     56.3                                                                             7.8   65.3                                                                               264 -0.30  -0.36                                       E 5178                                                                         (e)  79.6 --  --  --    --  -0.28  -0.35                                       E 5005                                                                         (f)  80   --  --  --    --  --     --                                          E 5487                                                                         (g)  90   42  7.3   53.3                                                                               144 -0.16  -0.33                                       E 5180                                                                         (h)  91.3 --  --  --    --  --     --                                          E 4913                                                                         (i)  104  --  --  --    --  --     --                                          E 4796                                                                         (k)  68.6                   -0.28  -0.40                                       E 5007                                                                         (e)  77.7 --  --  --    --  --     --                                          E 4575                                                                         (l)  79.6 --  --  --    --  --     --                                          E 4574                                                                         (E 3752)                                                                       (m)  62   45  5   50    150 -0.47  -0.58                                       A 28NZ                                                                         __________________________________________________________________________

                                      TABLE II                                     __________________________________________________________________________     Amorphous copolyamide (type XE 3038) derived from hexamethylenediamine/iso     phthalic                                                                       acid with impact-resistance-modifier (impact-resistance-modifier as in         Table I)                                                                       __________________________________________________________________________                             5    6   7                                                       2        4    Impact                                                                              Notch                                                                              Bending                                                 Impact-                                                                             3   Melt Resis-                                                                              Impact                                                                             E Modu-                                                                             8                                              1   Resis-                                                                              Digly-                                                                             Viscos-                                                                             tance                                                                               Resist                                                                             lus  Limit                                    0     Poly-                                                                              tance                                                                               cidyl                                                                              ity  23° C./                                                                      23° C./                                                                     23° C./                                                                      Bending                                  Test  amid-                                                                              modifier                                                                            ether                                                                              (270°/                                                                       dry  dry dry  Stress                                   No.   wt. %                                                                              wt. %                                                                               wt. %                                                                              122.6N)                                                                             kJ/m2                                                                               kJ/m2                                                                              N/mm2                                                                               N/mm2                                    __________________________________________________________________________     (a) A2771                                                                            100  0   0   1755 40% nb                                                                               1.5                                                                               2960 166                                      XE 3038                 60% 60                                                 (b)   99.7                                                                                0   0.3 2643 40% nb                                                                               1.6                                                                               3120 125                                      E 6248                  60% 58                                                 (c)   86.8                                                                               13   0.2 2643 nb   47.0                                                                               2350 114                                      E 6248                                                                         (d) E4471                                                                            85  15   --  --   nb   38  1991   100.3                                  E 6603                                                                         (e)   84.8                                                                               15   0.2 2994 nb   51.3                                                                               2238 110                                      E 5864                                                                         (f)   84.7                                                                               15   0.3 3407 nb   49.2                                                                               2241 112                                      E 5864                                                                         (g)   84.6                                                                               15   0.4 4440 nb   49.9                                                                               2288 114                                      E 5866                                                                         (h)   80  20   --  4027 nb   42.2                                                                               1880  93                                      E 5275                                                                         (i)   79.9                                                                               20   0.1 4801 nb   43.6                                                                               1920  92                                      E 6753                                                                         (k)   79.8                                                                               20   0.2 --   nb   45.6                                                                               2110 102                                      E 6601                                                                         (l)   84.7                                                                               15   0.3 4130 nb   47.1                                                                               2299 114                                      E 5867                                                                         __________________________________________________________________________                             13     14                                                        10        12  Longi- Longi-                                                                               15                                              9   Elon-                                                                              11    Exten-                                                                             tudinal                                                                               tudinal                                                                              %                                               Yield                                                                              gation                                                                             Tensile                                                                              sion                                                                               Shrink-                                                                               Shrink-                                                                              Injection                                 0     Stress                                                                             at  Strength                                                                             at  age    age   Shrinkage                                 Test  23° C./                                                                     Yield                                                                              23° C./dry                                                                    Break                                                                              after  after after                                     No.   dry %   N/mm2 %   24 h/100° C.                                                                   1 h/140° C.                                                                   24 h                                      __________________________________________________________________________     (a) A2771                                                                            110  10.5                                                                              70    62  0.0132  -0.332                                                                              +0.218                                    XE 3038                                                                        (b)   --  --  --    --  -0.33  -1.1                                            E 6248                                                                         (c)   73  8   55    25  -0.05   -0.54                                          E 6248                                                                         (d) E4471                                                                            --  --  --    --  +.17   -2.0-4.0                                        E 6603                                                                         (e)   68  9   55    46  -0.092 -3.8                                            E 5864                                                                         (f)   70  7   57    61  -0.07  -3.1  +0.315                                    E 5864                                                                         (g)   70  7   54    25  -0.03  -2.6                                            E 5866                                                                         (h)   65  7   56    65  +0.188 -5.0-8.0                                                                             -0.5-0.                                   E 5275                                                                         (i)   --  --  --    --  +0.02  -3.9  +0.374                                    E 6753                                                                         (k)   67    6.5                                                                              56     8  -0.071  -2.36                                          E 6601                                                                         (l)   70    8.5                                                                              53    18  -0.04  -3.6                                            E 5867                                                                         __________________________________________________________________________

                                      TABLE III                                    __________________________________________________________________________     Amorphous Copolyamide TR55 (impact-resistance-modifier as in Table             __________________________________________________________________________     I)                                                                                                     5    6   7                                                       2        4    Impact                                                                              Notch                                                                              Bending                                                 Impact-                                                                             3   Melt Resis-                                                                              Impact                                                                             E Modu-                                                                             8                                              1   Resis-                                                                              Digly-                                                                             Viscos-                                                                             tance                                                                               Resist                                                                             lus  Limit                                    0     Poly-                                                                              tance                                                                               cidyl                                                                              ity  23° C./                                                                      23° C./                                                                     23° C./                                                                      Bending                                  Test  amid-                                                                              modifier                                                                            ether                                                                              (270°/                                                                       dry  dry dry  Stress                                   No.   wt. %                                                                              wt. %                                                                               wt. %                                                                              122.6N)                                                                             kJ/m2                                                                               kJ/m2                                                                              N/mm2                                                                               N/mm2                                    __________________________________________________________________________     (a)   100  0   0   1200-1500                                                                           nb    5.0                                                                               2100 118                                      TR55                                                                           (b) E5428                                                                            99.7                                                                                0   0.3 2189 nb    5.26                                                                              2160 --                                       E5716 99.7                                                                                0   0.3 1241 nb    5.09                                                                              2080 119                                      (c)   99.6                                                                                0   0.4 1446 nb    5.03                                                                              2190 --                                       E 5482                                                                         (d)   90  10   --  1516 nb   21.9                                                                               1730 101                                      F3-55                                                                          (e)   89.7                                                                               10   0.3 3511 nb   23.8                                                                               1860 98                                       E 6180                                                                         (f)   85  15   --  1454 nb   30.9                                                                               1737 89                                       F3-56                                                                          (g)   84.6                                                                               15   0.4 2601 nb   34.9                                                                               1780 88                                       E 5255                                                                         (h)   80  20   --  1755 nb   37.7                                                                               1504 77                                       F3-57                                                                          (i)   79.6                                                                               20   0.4 2815 nb   40.2                                                                               1800 95                                       E 7287                                                                         __________________________________________________________________________                             13     14                                                        10        12  Longi- Longi-                                                                               15                                              9   Elon-                                                                              11    Exten-                                                                             tudinal                                                                               tudinal                                                                              %                                               Yield                                                                              gation                                                                             Tensile                                                                              sion                                                                               Shrink-                                                                               Shrink-                                                                              Injection                                 0     Stress                                                                             at  Strength                                                                             at  age    age   Shrinkage                                 Test  23° C./                                                                     Yield                                                                              23° C./dry                                                                    Break                                                                              after  after after                                     No.   dry %   N/mm2 %   24 h/100° C.                                                                   1 h/140° C.                                                                   24 h                                      __________________________________________________________________________     (a)   75   8  60    30  -0.07  -0.09 0.8-1.0                                   TR55                                                                           (b) E5428                                                                            --  --  --    --  --     --                                              E5716 80  11  55    24                                                         (c)   --  --  --    --  -0.16  0.4                                             E 5482                                                                         (d)   64  20  54    33  -0.30  -1.3  -0.5                                      F3-55                                                                          (e)   64  10  50    50  -0.08  -0.36 -0.36                                     E 6180                                                                         (f)     50.7                                                                             21  48    36  -0.50  -1.2  -0.53                                     F3-56                                                                          (g)   60  10  52    82  -0.23  - 0.98                                          E 5255                                                                         (h)   21  22  44    36  -0.58  -2.6  -0.69                                     F3-57                                                                          (i)   68  18  57    28   -0.073                                                                               -0.24 -0.40                                     E 7287                                                                         __________________________________________________________________________

                                      TABLE IV                                     __________________________________________________________________________     Polyamide 12 with impact-resistance-modifier (impact-resistance-modifier       as in Table I)                                                                 __________________________________________________________________________                               5    6    7                                                    2         4     Impact                                                                              Notch                                                                               Bending                                              Impact-                                                                             3    Melt  Resis-                                                                              Impact                                                                              E Modu-                                         1    Resis-                                                                              Digly-                                                                              Viscos-                                                                              tance                                                                               Resist                                                                              lus                                        0    Poly-                                                                               tance                                                                               cidyl                                                                               ity   23° C./                                                                      23° C./                                                                      23° C./                             Test amid-                                                                               modifier                                                                            ether                                                                               (270°/                                                                        dry  dry  dry                                        No.  wt. %                                                                               wt. %                                                                               wt. %                                                                               122.6N)                                                                              kJ/m2                                                                               kJ/m2                                                                               N/mm2                                      __________________________________________________________________________     Gril-                                                                               100  --   --         nb   14.4 1256                                       amid                                                                           (a) L25                                                                        (b)   99.75                                                                              --    0.25                                                                               1853  nb   15.6 1420                                       E6413                                                                          (c)  99.6 --   0.4  --    nb   23.2 1680                                       E5254                                                                          (d)  91.7  8   0.3  3698  nb   72.8 1350                                       E6424                                                                          (e)  89.7 10   0.3  3089  nb   65.3 1290                                       E6423                                                                          (f)  86.0 10   4.0  >10000                                                                               nb   nb   2243                                       E3535                                                                          (g)  90   10   --    320  nb   nb    380                                       E3536                                                                          __________________________________________________________________________                                  13     14                                                      10        12    Longi- Longi-                                         8    9   Elon-                                                                              11    Exten-                                                                               tudinal                                                                               tudinal                                        Limit                                                                               Yield                                                                              gation                                                                             Tensile                                                                              sion  Shrink-                                                                               Shrink-                                    0   Bending                                                                             Stress                                                                             at  Strength                                                                             at    age    age                                        Test                                                                               Stress                                                                              23° C./                                                                     Yield                                                                              23° C./dry                                                                    Break after  after                                      No. N/mm2                                                                               dry %   N/mm2 %     24 h/100° C.                                                                   1 h/140° C.                         __________________________________________________________________________     Gril-                                                                              64   44  9   47    178   +0.25  +0.9                                       amid                                                                           (a) L25                                                                        (b) 65   45  7   44    126   +0.20   +0.82                                     E6413                                                                          (c) 72   50  7   60    153   +0.13  +0.5                                       E5254                                                                          (d) 60   40  8   44    120   -0.14  +0.8                                       E6424                                                                          (e) 57   38  10  46    140   -0.24  -0.6                                       E6423                                                                          (f) 122  --  --  --    --    --     --                                         E3535                                                                          (g) 58   38  23  42    280   -0.36   +1.15                                     E3536                                                                          __________________________________________________________________________

                                      TABLE V                                      __________________________________________________________________________     Polyamide 6 with impact-resistance-modifier derived from core-sheath           polymers                                                                       __________________________________________________________________________                              5    6     7                                                    2         4    Impact                                                                              Notch Bending                                              Impact-                                                                             3    Melt Resis-                                                                              Impact                                                                               E Modu-                                         1    Resis-                                                                              Digly-                                                                              Viscos-                                                                             tance                                                                               Resist                                                                               lus                                        0    Poly-                                                                               tance                                                                               cidyl                                                                               ity  23° C./                                                                      23° C./                                                                       23° C./                             Test amid-                                                                               modifier                                                                            ether                                                                               (270°/                                                                       dry  dry   dry                                        No.  wt. %                                                                               wt. %                                                                               wt. %                                                                               122.6N)                                                                             kJ/m2                                                                               kJ/m2 N/mm2                                      __________________________________________________________________________     (a)  100  --   --   350  nb    4.0  2000                                       A28 pure                                                                       (b)  91.6  8   0.4  372  nb    7.3  2570                                       E 5253                                                                         (c)  89.6 10   0.4  454  nb   14.4  2360                                       E 5004                                                                         (d)  84.6 15   0.5  --   nb   18.5  2380                                       E 5223                                                                         (e)  75   25   --   434  nb   38    1572                                       A28 NT                                                                         (f)  74.6 25   0.4  2394 nb   60% nb                                                                               1698                                       E 5008                        40% 50                                           (h)  72   25   3.0  5369 nb   42.8  2005                                       E 4572                                                                         (i)  70   25   5.0  --   nb   nb    1974                                       E 5473                                                                         __________________________________________________________________________                                 13     14                                                        10        12  Longi- Longi-                                           8    9   Elon-                                                                              11    Exten-                                                                             tudinal                                                                               tudinal                                          Limit                                                                               Yield                                                                              gation                                                                             Tensile                                                                              sion                                                                               Shrink-                                                                               Shrink-                                     0    Bending                                                                             Stress                                                                             at  Strength                                                                             at  age    age                                         Test Stress                                                                              23° C./                                                                     Yield                                                                              23° C./dry                                                                    Break                                                                              after  after                                       No.  N/mm2                                                                               dry %   N/mm2 %   24 h/100° C.                                                                   1 h/140° C.                          __________________________________________________________________________     (a)  100  83  10  55    30  -0.36  -0.75                                       A28 pure                                                                       (b)  106  73  7   54    10  -0.28  -0.48                                       E 5253                                                                         (c)  97 ` --  --  --    --  -0.40  -0.50                                       E 5004                                                                         (d)  91   63  7   51    123 -0.42  -0.34                                       E 5223                                                                         (e)  66.2 45  5   40    110 -0.65  -0.57                                       A28 NT                                                                         (f)  69.6 --  --  --    --  -0.48  -0.39                                       E 5008                                                                         (h)  78.5 --  --  --    --  --     --                                          E 4572                                                                         (i)  76.8 --  --  --    --  --     --                                          E 5473                                                                         __________________________________________________________________________

                                      TABLE VI                                     __________________________________________________________________________     Polyamide 6 with impact-resistance-modifier (C elastomeric copolyolefine       type) and diglycidyl ether                                                                        4    5    6                                                           2        Melt Impact                                                                              Notch                                                                               7              10        12                            Impact-                                                                             3   Viscos-                                                                             Resis-                                                                              Impact                                                                              Bending                                                                             8    9    Elon-                                                                               11   Exten-                   1    Resis-                                                                              Digly-                                                                             ity  tance                                                                               Resist                                                                              E Modu-                                                                             Limit                                                                               Yield                                                                               gation                                                                              Tensile                                                                             sion                0    Poly-                                                                               tance                                                                               cidyl                                                                              (270°/                                                                       23° C./                                                                      23° C./                                                                      lus  Bending                                                                             Stress                                                                              at   Strength                                                                            at                  Test amid-                                                                               modifier                                                                            ether                                                                              122.6N)                                                                             dry  dry  23° C./                                                                      Stress                                                                              23° C./                                                                      Yield                                                                               23° C./dry                                                                   Break               No.  wt. %                                                                               wt. %                                                                               wt. %                                                                              kJ/m2                                                                               kJ/m2                                                                               N/mm2                                                                               dry  N/mm2                                                                               dry  %    N/mm2                                                                               %                   __________________________________________________________________________     A28NZ                                                                               80%  20   --  136  nb   42   1517 62   45   5    50   150                 E7716                                                                               84.2%                                                                               15   0.8%                                                                               814  nb   44.4 1951 78   56   6    62   150                                G1302                                                           E7718                                                                               79.2%                                                                               20   0.8%                                                                               2808 nb   53.8 1760 69   48   7    51   135                                G1302                                                           __________________________________________________________________________ 

What we claim is:
 1. A rigid molding composition consisting essentially of a thermoplastic processible polyamide, an elastomer, and an epoxy having a plurality of epoxide groups, said epoxy has the formula

    Y--O--X--O--Y

wherein Y is an epoxide carrying radical and X is a divalent radical taken from the class consisting of alkyl of two to ten carbon atoms and aralkyl of seven to twenty carbon atoms, wherein said elastomer is at least one copolymer of an α-olefin grafted with an unsaturated dicarboxylic acid, said elastomer comprising 3 to 20 percent by weight of said composition.
 2. The composition of claim 1 wherein said polyamide comprises at least 40% by weight of said composition.
 3. The composition of claim 1 wherein said amount is 10 to 20%.
 4. The composition of claim 1 wherein said epoxy is neopentyl diglycidyl ether, bisphenol A derived diglycidyl ether, or a mixture thereof.
 5. The composition of claim 1 wherein said epoxy comprises 0.01 to 15% by weight of said composition.
 6. The composition of claim 5 wherein said epoxy comprises 0.05 to 5.0% by weight of said composition.
 7. The composition of claim 1 wherein said copolyolefin comprises a maximum of 90 mol % ethylene and is grafted with a maximum of 1 mol % of unsaturated dicarboxylic acid thereby providing a maximum of 2 mol % active carboxylic groups.
 8. The composition of claim 6 wherein said epoxy comprises 0.1 to 1.0% by weight of said composition. 